Fix powerpc and LINT builds

Fix build errors introduced by r367417 and r367390:

- Guard label reached only by powerpc64
- Guard vm_reserv_level_iffullpop call, that is not defined on powerpc
  variants that don't support superpages
- Add missing hwpmc file, for when hwpmc is built into kernel

sys/conf/files.powerpc

@@ -26,6 +26,7 @@ dev/agp/agp_apple.c		optional	agp powermac
 dev/fb/fb.c			optional	sc
 dev/hwpmc/hwpmc_e500.c		optional	hwpmc
 dev/hwpmc/hwpmc_mpc7xxx.c	optional	hwpmc
+dev/hwpmc/hwpmc_power8.c	optional	hwpmc
 dev/hwpmc/hwpmc_powerpc.c	optional	hwpmc
 dev/hwpmc/hwpmc_ppc970.c	optional	hwpmc
 dev/iicbus/ad7417.c		optional	ad7417 powermac

sys/powerpc/aim/mmu_oea64.c

@@ -1760,6 +1760,7 @@ moea64_enter(pmap_t pmap, vm_offset_t va, vm_page_t m,
 		moea64_syncicache(pmap, va, pa, PAGE_SIZE);
 	}
 
+#if VM_NRESERVLEVEL > 0
 	/*
 	 * Try to promote pages.
 	 *
@@ -1773,6 +1774,7 @@ moea64_enter(pmap_t pmap, vm_offset_t va, vm_page_t m,
 	    (m->flags & PG_FICTITIOUS) == 0 &&
 	    vm_reserv_level_iffullpop(m) == 0)
 		moea64_sp_promote(pmap, va, m);
+#endif
 
 	return (KERN_SUCCESS);
 }

sys/powerpc/aim/moea64_native.c

@@ -211,6 +211,8 @@ TLBIE(uint64_t vpn, uint64_t oldptehi)
 	 */
 	__asm __volatile("li 0, 0 \n tlbie %0, 0" :: "r"(vpn) : "r0", "memory");
 	__asm __volatile("eieio; tlbsync; ptesync" ::: "memory");
+done:
+
 #else
 	vpn_hi = (uint32_t)(vpn >> 32);
 	vpn_lo = (uint32_t)vpn;
@@ -235,7 +237,6 @@ TLBIE(uint64_t vpn, uint64_t oldptehi)
 	intr_restore(intr);
 #endif
 
-done:
 	/* No barriers or special ops -- taken care of by ptesync above */
 	if (need_lock)
 		tlbie_lock = 0;